The present invention relates to signature stackers and, more particularly, to a stacking apparatus with rotary intercept and a method for using it to form batches of signatures.
In the newspaper industry, such stackers are used to receive a stream of overlapped signatures from an infeed conveyor and form the overlapped signatures into discrete batches of stacked signatures. One critical aspect of this process is to intercept the stream of signatures at a precise time in order to form a new batch of signatures which is separated from the previous batch of signatures.
One known signature stacker having a rotary intercept assembly is disclosed in U.S. Pat. No. 4,037,525 to Sjogren et al., which is incorporated herein by reference. A commercial embodiment of that stacker is made by IDAB Incorporated and is known as the IDAB Model 440 stacker. As shown in that patent, the intercept blade assembly of the Model 440 stacker is driven through a clutch assembly by a constant speed A.C. motor. That intercept blade assembly is preloaded by torsion springs and is held preloaded by a retractable stop plate. When the stop plate is retracted, the preloaded intercept blade is abruptly urged into the path of a stream of signatures which is received from an infeed conveyor. The signatures otherwise would have continued to be stacked on a reciprocating stacking blade assembly. When the intercept blade of the IDAB Model 440 stacker is abruptly urged into the intercept position and begins collecting signatures, the infeed conveyor must be raised or elevated to facilitate a proper collection of signatures on the intercept blade.
The intercept assembly for the 440 stacker is complex and requires a large number of moving parts as well as a relatively complicated control mechanism to accomplish the intercept motion of the intercept blade.
Accordingly, it is an object of the present invention to provide a simplified intercept assembly which is more accurate, more predictable, and more reliable.
Additional objects and advantages of the invention will be set forth in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.